Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func HashToZn ¶
HashToZn hashes an arbitrary message to a scalar in Z_N (the secp256k1 group order).
func VerifyRandomness ¶
VerifyRandomness verifies that the provided randomness corresponds to the provider's public key and nonce. Used for off-chain checks; actual verification is done by the VRFVerifier contract on-chain.
Full verification requires four independent checks:
- U == c·pk + s·G (prover knows sk such that pk = sk·G)
- CGamma == c·gamma (CGamma is correctly derived from gamma and c)
- V == CGamma + s·h (V is correctly derived from gamma, h, c, s)
- c == HashToZn(Pack(G, h, pk, gamma, U, V))
Types ¶
type Point ¶
func HashToCurve ¶
HashToCurve hashes an arbitrary message to a point in an elliptic group.
func ScalarBaseMult ¶
ScalarBaseMult returns k*G, where G is the base point of the group and k is an integer.
func ScalarMult ¶
ScalarMult returns k*P, where P is provided point of the group and k is an integer.
func (*Point) ValidatePoint ¶
ValidatePoint checks that the point is non-nil and lies on the secp256k1 curve.
type Proof ¶
type Proof struct {
Gamma *Point // gamma = sk · HashToCurve(nonce)
C *big.Int // challenge scalar
S *big.Int // response scalar s = k − sk·c mod N
// Witness points (computed off-chain, verified on-chain via ecrecover)
U *Point // u = c·pk + s·G
CGamma *Point // c·gamma (intermediate for verifying V)
V *Point // v = c·gamma + s·h
ZInv *big.Int // modInv(CGamma.X − V.X, P); field element in [1, P)
}
Proof represents a generated verifiable randomness together with a proof of its correctness. It mirrors the Proof struct in VRFVerifier.sol.
The four witness points (U, CGamma, V, ZInv) are pre-computed by VerifiableRandomness and are required by the on-chain VRFVerifier contract to avoid expensive secp256k1 scalar multiplications or BigModExp inside the EVM.
func VerifiableRandomness ¶
func VerifiableRandomness(key *ecdsa.PrivateKey, nonce []byte) (*Proof, error)
VerifiableRandomness creates a deterministic verifiable randomness (with proof) given a private key and a nonce.
Source Files